Physical laws mean that it is generally impossible to identify which power stations are exporting to another country, but economic logic offers strong clues. On windy days, Denmark tends to export electricity to its neighbours, and to import power on calm days. Storing electricity in this way...

Starting in 1998, the electricity market in England and Wales will be opened up to full competition, and all consumers will be allowed to choose their electricity supplier. This promises to result in lower prices, but there will be additional transactions costs exceeding £100 million a year for...